The general long-term goal is the elucidation of the molecular interactions organizing DNA packaging in chromosomes and the elucidation of interactions organizing the chromosome structure itself. Emphasis in this project is on defining the prokaryotic proteins that package DNA and on determining the topological restraints imposed on the DNA by these proteins. A new approach is to be developed for isolating plasmid DNA molecules having DNA packaged in a native form and for identifying the proteins responsible for this structure. Other experiments using differential decay of birefringence measurements will determine the relative compaction of DNA due to binding histone-like proteins HU, H and HLP1 singly or together. The DNA twist and writhe brought about by these proteins will also be determined. Another emphasis is on elucidating the functions of certain eukaryotic non-histone chromosomal proteins believed to be structural proteins of the nuclear matrix or chromosome scaffold. Monoclonal antibodies specific for these proteins will be micorinjected into living cells to perturb the normal interactions of these proteins and thereby indicate their roles.